* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  height: 100vh;
  /* 弹性布局 水平+垂直居中 */
  display: flex;
  justify-content: center;
  align-items: center;
  /* 渐变背景 */
  background: linear-gradient(to top, #fff, #c2e9fb);
}
#slider {
  position: absolute;
  padding: 30px 0;
}
#range {
  position: relative;
  top: 0;
  left: 0;
  color: black;
}
